Investigators from BART and the National Transportation Safety Board use mannequins during a re-enactment of Saturday's accident that killed two workers, Wednesday, Oct. 23, 2013 in Walnut Creek, Calif. NTSB investigators conducted the re-enactment and a sight/distance study to gather more details of the incident.

BART trains will be required to slow down, stop or change course as they approach track maintenance workers following the deaths of two inspectors who were struck during a labor strike last weekend, the agency said Thursday.

BART Assistant General Manager Paul Oversier told the transit district's board of directors that the new rule will replace the previous practice of making workers solely responsible for their own safety as they walk or perform simpler tasks on the tracks of the commuter rail line.

"Fortunately, the fatalities we have are few and far between," he said. "That said, obviously one is too many."

The two workers, both experienced transportation engineers, had received what BART calls "simple approval" on Saturday to inspect an above-ground section of track between two stations in the Easy Bay city of Walnut Creek where a dip in the rails had been reported.

Under that process, one worker is supposed to be designated as a lookout and to stand away from the tracks to warn the other of an oncoming train. Teams also are required to have a plan for getting out of harm's way in 15 seconds.

"It is the primary mechanism people use for traveling by foot along the railway," said Oversier, who estimated the procedure is used hundreds of times every month.

Requiring train operators and the control center to share responsibility for track worker safety is bound to cause service delays, but "we can't live with a continuation of this situation and what happened on Saturday," Oversier said during an interview with The Associated Press.

"The impact on the reliability of the service will be a negative one, but at this point we don't see any other alternative, and we think that's just the way it had to be and we have to bite that bullet," he said.

Federal safety investigators who are reviewing the events leading up the accident have said the train that struck the workers was traveling 60 to 70 mph and did not have to slow down or observe any safety signals as it approached them.

The workers -- Christopher Sheppard, 58, a BART track engineer, and Laurence Daniels, 66, a contract employee -- also did not have radios or other communications device to alert them when a train was approaching, National Transportation Safety Board investigator Paul Southworth said.

The NTSB has said that a person learning to operate the train was running it under computer control instead of manually when it hit the two men. It was on a maintenance run and was not carrying passengers due to the transit agency's strike.

The operator heard an announcement just before the accident that there were people on the tracks, Southworth said. A horn was sounded and emergency brakes were applied, and so far no mechanical problems have been discovered, he said.

Under the new procedures, which until now had been reserved for more complicated or lengthy tasks, train operators have to slow down to 27 mph or less until they know it is safe to proceed, according to a memo issued to people who work in BART's control center.

To further protect workers, trains might also have to stop, be operated manually or rerouted around job sites using single-tracking, the memo said.

In 2008, after the death of another track worker, BART considered outfitting employees with armbands and transponders that would signal them when a train was approaching, Oversier said. The devices were not adopted because the transit agency and its unions concluded they would not add to the level of safety that existed then, he said.

The agency plans to review technological approaches that might have been developed since then, he said.